Dishwashing appliance with decision making via sensor circuit

ABSTRACT

A method of operating a dishwashing appliance includes activating a pump for a predefined self-calibration time by supplying electrical power from a power supply to a motor of the pump. The method also includes monitoring, with the sensor circuit, electrical power between the power supply and the motor while the pump is activated for the predefined self-calibration time. The method further includes determining, based on the monitored electrical power, a motor type of the motor and selecting a set of control parameters corresponding to the determined motor type of the motor. The method also includes activating the pump according to the selected set of control parameters during at least one cycle of the dishwashing appliance.

FIELD OF THE INVENTION

The present subject matter relates generally to dishwashing appliances, and more particularly to features and methods for detecting a motor type in dishwashing appliances.

BACKGROUND OF THE INVENTION

Dishwashing appliances generally include a tub that defines a wash chamber. Rack assemblies can be mounted within the wash chamber of the tub for receipt of articles for washing. Multiple spray assemblies can be positioned within the wash chamber for applying or directing wash liquid (e.g., water, detergent, etc.) towards articles disposed within the rack assemblies in order to clean such articles. Dishwashing appliances are also typically equipped with one or more pumps, such as a circulation pump or a drain pump, for directing or motivating wash liquid from the sump to, e.g., the spray assemblies or an area outside of the dishwashing appliance.

The one or more pumps are driven by one or more respective motors. Each pump may be physically compatible with multiple different types of motor, however, the different motor types may require different control parameters for optimal operation. Conventional dishwashing appliances are manually programmed to operate the specific pump motor which is installed at the time of manufacture. In some cases, the pump motor may be changed or replaced, resulting in a pump motor which is physically compatible with the pump but for which the optimal control parameters may not be actively loaded into or applied by the controller of the dishwashing appliance. Such instances may lead to suboptimal pump motor performance.

Accordingly, dishwashing appliances that include features for automatically detecting a motor type would be useful.

BRIEF DESCRIPTION OF THE INVENTION

Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

In one exemplary aspect of the present disclosure, a method of operating a dishwashing appliance is provided. The dishwashing appliance includes a tub defining a wash chamber therein for receipt of articles for washing. A sump is positioned at a bottom of the wash chamber for receiving fluid from the wash chamber. The dishwashing appliance also includes a pump in communication with the wash chamber and the sump. The pump includes a motor. The dishwashing appliance further includes a sensor circuit. The method includes activating the pump for a predefined self-calibration time by supplying electrical power from a power supply to the motor of the pump. The method also includes monitoring, with the sensor circuit, electrical power between the power supply and the motor while the pump is activated for the predefined self-calibration time. The method further includes determining a motor type of the motor based on the monitored electrical power. The method also includes selecting a set of control parameters corresponding to the determined motor type of the motor and activating the pump according to the selected set of control parameters during at least one cycle of the dishwashing appliance.

In another exemplary aspect of the present disclosure, a dishwashing appliance is provided. The dishwashing appliance includes a tub defining a wash chamber therein for receipt of articles for washing. A sump is positioned at a bottom of the wash chamber for receiving fluid from the wash chamber. The dishwashing appliance also includes a pump in communication with the wash chamber and the sump. The pump includes a motor. The dishwashing appliance further includes a sensor circuit and a controller. The controller is configured for activating the pump for a predefined self-calibration time by supplying electrical power from a power supply to the motor of the pump. The controller is also configured for monitoring, with the sensor circuit, electrical power between the power supply and the motor while the pump is activated for the predefined self-calibration time. The controller is further configured for determining a motor type of the motor based on the monitored electrical power. The controller is also configured for selecting a set of control parameters corresponding to the determined motor type of the motor and activating the pump according to the selected set of control parameters during at least one cycle of the dishwashing appliance.

These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures.

FIG. 1 provides a front view of an exemplary embodiment of a dishwashing appliance of the present disclosure.

FIG. 2 provides a perspective view of an additional exemplary embodiment of a dishwashing appliance of the present disclosure with a door in an intermediate position.

FIG. 3 provides a side, cross section view of an exemplary dishwashing appliance, such as the dishwashing appliance of FIG. 1 or FIG. 2 .

FIG. 4 provides a schematic diagram of an exemplary sensor circuit according to one or more embodiments of the present disclosure which may be incorporated into a dishwashing appliance such as the exemplary dishwashing appliance of FIGS. 1 through 3 .

FIG. 5 provides an exemplary graph of electrical current over time for a first exemplary motor type according to one or more exemplary embodiments of the present disclosure.

FIG. 6 provides another exemplary graph of electrical current over time for a second exemplary motor type according to one or more exemplary embodiments of the present disclosure.

FIG. 7 provides a flow chart of a method of operating a dishwashing appliance according to one or more exemplary embodiments of the present disclosure.

DETAILED DESCRIPTION

Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.

As used herein, the term “or” is generally intended to be inclusive (i.e., “A or B” is intended to mean “A or B or both”). The terms “first,” “second,” and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. The terms “upstream” and “downstream” refer to the relative flow direction with respect to fluid flow in a fluid pathway. For instance, “upstream” refers to the flow direction from which the fluid flows, and “downstream” refers to the flow direction to which the fluid flows. The term “article” may refer to, but need not be limited to dishes, pots, pans, silverware, and other cooking utensils and items that can be cleaned in a dishwashing appliance. The term “wash cycle” is used to refer to an overall operation of the dishwashing appliance which may include two or more distinct phases. The term “wash phase” is intended to refer to one or more periods of time during which a dishwashing appliance operates while containing the articles to be washed and uses a wash liquid (e.g., water, detergent, or wash additive) and may be a portion of the wash cycle, such as a beginning or early portion of the wash cycle. The term “rinse phase” is intended to refer to one or more periods of time during which the dishwashing appliance operates to remove residual soil, detergents, and other undesirable elements that were retained by the articles after completion of the wash phase and may be a portion of the wash cycle, such as an intermediate portion of the wash cycle. The term “drain phase” is intended to refer to one or more periods of time during which the dishwashing appliance operates to discharge soiled water from the dishwashing appliance and may be a portion of the wash cycle, such as a later portion of the wash cycle. The term “wash liquid” refers to a liquid used for washing or rinsing the articles that is typically made up of water and may include additives, such as detergent or other treatments (e.g., rinse aid). Furthermore, as used herein, terms of approximation, such as “generally,” “approximately,” “substantially,” or “about,” refer to being within a ten percent (10%) margin of error. When used in the context of an angle or direction, such terms include within ten degrees greater or less than the stated angle or direction, e.g., “generally vertical” includes forming an angle of up to ten degrees in any direction, e.g., clockwise or counterclockwise, with the vertical direction V.

Turning now to the figures, FIGS. 1 through 3 depict an exemplary dishwasher or dishwashing appliance (e.g., dishwashing appliance 100) that may be configured in accordance with aspects of the present disclosure. Generally, dishwasher 100 defines a vertical direction V, a lateral direction L, and a transverse direction T. Each of the vertical direction V, lateral direction L, and transverse direction T are mutually perpendicular to one another and form an orthogonal direction system.

Dishwasher 100 includes a tub 104 that defines a wash chamber 106 therein. As shown in FIG. 3 , tub 104 extends between a top 107 and a bottom 108 along the vertical direction V, between a pair of side walls 110 along the lateral direction L, and between a front side 111 and a rear side 112 along the transverse direction T.

Tub 104 includes a front opening 114 at the front side 111. In some embodiments, the dishwashing appliance 100 may also include a door 116 at the front opening 114. The door 116 may, for example, be coupled to the tub 104 by a hinge 200 at its bottom for movement between a normally closed vertical position (FIGS. 1 and 3 ), wherein the wash chamber 106 is sealed shut for washing operation, and a horizontal open position (not shown) for loading and unloading of articles from dishwasher 100. A door closure mechanism or assembly 118, e.g., a latch, may be provided to lock and unlock door 116 for accessing and sealing wash chamber 106.

In exemplary embodiments, tub side walls 110 accommodate a plurality of rack assemblies. For instance, guide rails 120 may be mounted to side walls 110 for supporting a lower rack assembly 122 and an upper rack assembly 126. In some such embodiments, upper rack assembly 126 is positioned at a top portion of wash chamber 106 above lower rack assembly 122 along the vertical direction V.

Generally, each rack assembly 122, 126 may be adapted for movement between an extended loading position (not shown) in which the rack is substantially positioned outside the wash chamber 106, and a retracted position (shown in FIGS. 1 through 3 ) in which the rack is located inside the wash chamber 106. In some embodiments, movement is facilitated, for instance, by rollers 128 mounted onto rack assemblies 122, 126, respectively.

Although guide rails 120 and rollers 128 are illustrated herein as facilitating movement of the respective rack assemblies 122, 126, it should be appreciated that any suitable sliding mechanism or member may be used according to alternative embodiments.

In optional embodiments, some or all of the rack assemblies 122, 126 are fabricated into lattice structures including a plurality of wires or elongated members 130 (for clarity of illustration, not all elongated members making up rack assemblies 122, 126 are shown). In this regard, rack assemblies 122, 126 are generally configured for supporting articles within wash chamber 106 while allowing a flow of wash liquid to reach and impinge on those articles (e.g., during a cleaning or rinsing phase of the wash cycle). According to additional or alternative embodiments, a silverware basket (not shown) may be removably attached to a rack assembly (e.g., lower rack assembly 122), for placement of silverware, utensils, and the like, that are otherwise too small to be accommodated by the rack assembly.

Generally, dishwasher 100 includes one or more spray assemblies for urging a flow of fluid (e.g., wash liquid) onto the articles placed within wash chamber 106.

In exemplary embodiments, dishwasher 100 includes a lower spray arm assembly 134 disposed in a lower region 136 of wash chamber 106 and above a sump 138 so as to rotate in relatively close proximity to lower rack assembly 122. In this regard, lower spray arm assembly 134 may generally be configured for urging a flow of wash liquid up through lower rack assembly 122.

In some embodiments, an upper spray assembly 142 may be located proximate to and, e.g., below, upper rack assembly 126 along the vertical direction V. In this manner, upper spray assembly 142 may be generally configured for urging of wash liquid up through upper rack assembly 126.

The various spray assemblies and manifolds described herein may be part of a fluid distribution system or fluid circulation assembly 150 for circulating wash liquid in tub 104. In certain embodiments, fluid circulation assembly 150 includes a circulation pump 152 for circulating wash liquid in tub 104. Circulation pump 152 may be mounted to sump 138 and in fluid communication with the sump 138 through a circulation outlet 151 from the sump 138.

When assembled, circulation pump 152 may be in fluid communication with an external water supply line (not shown) and sump 138. A water inlet valve (not shown) can be positioned between the external water supply line and circulation pump 152 (e.g., to selectively allow water to flow from the external water supply line to circulation pump 152). Additionally or alternatively, water inlet valve can be positioned between the external water supply line and sump 138 (e.g., to selectively allow water to flow from the external water supply line to sump 138). During use, water inlet valve may be selectively controlled to open to allow the flow of water into dishwasher 100 and may be selectively controlled to close and thereby cease the flow of water into dishwasher 100. Further, fluid circulation assembly 150 may include one or more fluid conduits or circulation piping for directing wash fluid from circulation pump 152 to the various spray assemblies and manifolds. In exemplary embodiments, such as that shown in FIG. 3 , a primary supply conduit 154 extends from circulation pump 152, along rear side 112 of tub 104 along the vertical direction V to supply wash liquid throughout wash chamber 106.

In optional embodiments, circulation pump 152 urges or pumps wash liquid to a diverter 156 (FIG. 3 ). In some such embodiments, diverter 156 is positioned within sump 138 of dishwashing appliance 100). Diverter 156 may include a diverter disk (not shown) disposed within a diverter chamber 158 for selectively distributing the wash liquid to the spray assemblies 134, 142, or other spray manifolds or assemblies. For instance, the diverter disk may have at least one aperture configured to align with one or more outlet ports (not shown) at the top of diverter chamber 158. In this manner, the diverter disk may be selectively rotated to provide wash liquid to the desired spray device(s).

In exemplary embodiments, diverter 156 is configured for selectively distributing the flow of wash liquid from circulation pump 152 to various fluid supply conduits—only some of which are illustrated in FIG. 3 for clarity. In certain embodiments, diverter 156 includes two or more outlet ports (not shown) for supplying wash liquid to a first conduit for rotating lower spray arm assembly 134 and a second conduit for supplying upper spray assembly 142 (e.g., supply conduit 154). Additional embodiments may also include one or more additional conduits, e.g., a third conduit for spraying an auxiliary rack such as a silverware rack, etc.

In some embodiments, a supply conduit 154 is used to supply wash liquid to one or more spray assemblies (e.g., to upper spray assembly 142). It should be appreciated, however, that according to alternative embodiments, any other suitable plumbing configuration may be used to supply wash liquid throughout the various spray manifolds and assemblies described herein. For instance, according to another exemplary embodiment, supply conduit 154 could be used to provide wash liquid to lower spray arm assembly 134 and a dedicated secondary supply conduit (not shown) could be utilized to provide wash liquid to upper spray assembly 142. Other plumbing configurations may be used for providing wash liquid to the various spray devices and manifolds at any location within dishwashing appliance 100.

Each spray assembly 134 and 142, or other spray device as may be included in dishwashing appliance 100, may include an arrangement of discharge ports or orifices for directing wash liquid received from circulation pump 152 onto dishes or other articles located in wash chamber 106. The arrangement of the discharge ports, also referred to as jets, apertures, or orifices, may provide a rotational force by virtue of wash liquid flowing through the discharge ports. Alternatively, spray assemblies 134, 142 may be motor-driven, or may operate using any other suitable drive mechanism. Spray manifolds and assemblies may also be stationary. The resultant movement of the spray assemblies 134, 142 and the spray from fixed manifolds provides coverage of dishes and other dishwasher contents with a washing spray. Other configurations of spray assemblies may be used as well. For instance, dishwasher 100 may have additional spray assemblies for cleaning silverware, for scouring casserole dishes, for spraying pots and pans, for cleaning bottles, etc.

Drainage of soiled wash liquid within sump 138 may by provided, for instance, by a drain pump 168 (e.g., during or as part of a drain phase). In particular, wash liquid may exit sump 138 through a drain outlet 167 and may flow through a drain conduit or directly to the drain pump 168. Thus, drain pump 168 is downstream of sump 138 and facilitates drainage of the soiled wash liquid by urging or pumping the wash liquid to a drain line external to dishwasher 100.

In some embodiments, a filter assembly may be provided, e.g., in the sump 138 and/or at a top entrance into the sump 138, e.g., to filter fluid to circulation assembly 150 and/or drain pump 168. Generally, the filter assembly removes soiled particles from the liquid that flows to the sump 138 from the wash chamber 106 during operation of dishwashing appliance 100. In exemplary embodiments, the filter assembly may include both a first filter (also referred to as a “coarse filter”) and a second filter (also referred to as a “fine filter”).

Although a separate circulation pump 152 and drain pump 168 are described herein, it is understood that other suitable pump configurations (e.g., using only a single pump for both recirculation and draining) may be provided.

The dishwashing appliance 100 may further include a heating element 184, such as a resistance heating element, positioned in or near the sump 138. For example, the heating element 184 may be positioned “near” the sump 138 in that the heating element 184 is disposed above the sump 138 and within the lower region 136 of wash chamber 106, such as below the lower spray arm 134 and/or below the lower rack assembly 122. The heating element 184 may be positioned and configured to heat liquid in the sump 138, such as for a heated wash phase, and/or to heat air within the wash chamber 106, such as for drying articles during a dry phase.

Dishwashing appliance 100 may also include ventilation features, e.g., to promote improved, e.g., more rapid, drying of articles therein after the wash and rinse phases. For example, one or more vents 170 may be provided in the tub 104 for introducing relatively dry air from outside of the tub 104 into the wash chamber 106 and/or for removing relatively humid air from the wash chamber 106 to the outside of the tub 104. In some embodiments, a fan 172 may be provided. The fan 172 may be operable to urge air through the wash chamber 106, such as to promote air circulation and/or ventilation within and through the wash chamber. Such air movement may increase the rate of evaporation of moisture from articles in the wash chamber 106 after a wash and/or rinse phase.

In certain embodiments, dishwasher 100 includes a controller 160 configured to regulate operation of dishwasher 100 (e.g., initiate one or more wash operations). Controller 160 may include one or more memory devices and one or more microprocessors, such as general or special purpose microprocessors operable to execute programming instructions or micro-control code associated with a wash operation or wash cycle that may include a pre-wash phase, a wash phase, a rinse phase, a drain phase, and/or a dry phase. The memory may represent random access memory such as DRAM, or read only memory such as ROM or FLASH. In some embodiments, the processor executes programming instructions stored in memory. The memory may be a separate component from the processor or may be included onboard within the processor. Alternatively, controller 160 may be constructed without using a microprocessor, e.g., using a combination of discrete analog or digital logic circuitry—such as switches, amplifiers, integrators, comparators, flip-flops, AND gates, and the like—to perform control functionality instead of relying upon software. It should be noted that controllers as disclosed herein are capable of and may be operable to perform any methods and associated method steps as disclosed herein.

Controller 160 may be positioned in a variety of locations throughout dishwasher 100. In optional embodiments, controller 160 is located within a control panel area 162 of door 116 (e.g., as shown in FIG. 1 or FIG. 2 ). Input/output (“I/O”) signals may be routed between the control system and various operational components of dishwasher 100 along wiring harnesses that may be routed through the bottom of door 116. Typically, the controller 160 includes or is operatively coupled to a user interface panel/controls 164 through which a user may select various operational features and modes and monitor progress of dishwasher 100. In some embodiments, user interface 164 includes a general purpose I/O (“GPIO”) device or functional block. In additional or alternative embodiments, user interface 164 includes input components, such as one or more of a variety of electrical, mechanical or electro-mechanical input devices including rotary dials, push buttons, and touch pads. In further additional or alternative embodiments, user interface 164 includes a display component, such as a digital or analog display device designed to provide operational feedback to a user. When assembled, user interface 164 may be in operative communication with the controller 160 via one or more signal lines or shared communication busses.

The dishwashing appliance 100 may also include a temperature sensor 186 in operative communication with the controller 160. For example, in some embodiments, the temperature sensor 186 may be located in the sump 138 and may thereby be operable to measure a temperature of a liquid, e.g., wash liquid, within the sump 138. For example, the “temperature sensor” may include any suitable type of temperature measuring system or device positioned at any suitable location for measuring the desired temperature. Thus, for example, temperature sensor 186 may be any suitable type of temperature sensor, such as a thermistor, a thermocouple, a resistance temperature detector, a semiconductor-based integrated circuit temperature sensor, etc. In addition, temperature sensor 186 may be positioned at any suitable location and may output a signal, such as a voltage, to the controller 160 that is proportional to and/or indicative of the temperature being measured. Although exemplary positioning of the temperature sensor 186 is described herein and depicted in FIG. 3 , it should be appreciated that dishwashing appliance 100 may include any other suitable number, type, and position of temperature, humidity, and/or other sensors as well as or instead of the exemplary temperature sensor 186 according to alternative embodiments.

It should be appreciated that the invention is not limited to any particular style, model, or configuration of dishwasher 100. The exemplary embodiments depicted in FIGS. 1 through 3 are for illustrative purposes only. For instance, different locations may be provided for control panel area 162 (e.g., on the front of the door 116 as illustrated in FIG. 1 or on the top of the door 116 as illustrated in FIG. 2 , or other locations as well), different configurations may be provided for rack assemblies 122, 126, different spray assemblies 134, 142 and spray manifold configurations may be used, different sensors may be used, and other differences may be applied while remaining within the scope of the present disclosure.

In some embodiments, the dishwashing appliance 100 may include a sensor circuit 204, e.g., such as the exemplary sensor circuit 204 illustrated in FIG. 4 . For example, the sensor circuit 204 may be coupled in-line between a power source 202 and a motor 214, and may also be coupled to the controller 160, as illustrated in FIG. 4 . The motor 214 may be, e.g., a pump motor, such as a motor of the circulation pump 152 and/or drain pump 168. The sensor circuit 204 may include a shunt resistor 206, e.g., which may sense or measure electric current to the motor 214 from the power source 202. With the sensor circuit 204 connected between the power source 202 and the motor 214 as shown and described, the voltage across shunt resistor 206 changes as the motor 214 turns on and off. The sensor circuit 204 may further include an operational amplifier (“op amp”) 208 and an amplifier 210 connected to the shunt resistor. The voltage across shunt resistor 206 may be conditioned by the op amp 208, e.g., in an instrumentation topology, and the conditioned voltage may be amplified by amplifier 210, e.g., in a difference amplifier topology. The sensor circuit 204 may further include a microcontroller 212, e.g., a slave microcontroller which communicates with the controller 160. For example, the microcontroller 212 may read the final (conditioned and amplified) voltage after the op amp 208 and the amplifier 210 and communicate such readings to the controller 160.

Referring now generally to FIGS. 5 and 6 , exemplary graphs of current over time for possible motors, e.g., a first motor type (Motor A, FIG. 5 ) and a second motor type (Motor B, FIG. 6 ) that is different from the first motor type, for the pump(s) of the dishwasher appliance 100. Such current over time may be measured, for example, by the sensor circuit 204 of FIG. 4 . As shown in FIGS. 5 and 6 , the sensor circuit 204 may be capable of measuring multiple aspects of the electrical power between the power supply 202 and the motor 214, such as the current drawn by the motor (shown in solid lines in FIGS. 5 and 6 ) and the back electromotive force (Back EMF) generated by the rotating motor, which is depicted in dashed lines in FIGS. 5 and 6 . Exemplary motor types which may be detected or distinguished according to various embodiments of the present disclosure include synchronous motors or brush motors, among other possible suitable motor types for a pump or pumps in a dishwashing appliance 100.

As mentioned above, the horizontal axes in FIGS. 5 and 6 represents time. For example, the time period may be a predefined self-calibration time which is separate from any wash cycles or washing operations of the dishwashing appliance 100. In some embodiments, the motor detection may be performed for the predefined self-calibration time at an initial startup of the dishwashing appliance 100, such as automatically when the dishwashing appliance 100 is powered on for the first time. In additional embodiments, the motor detection may also or instead be performed on demand, e.g., in response to a command or input received from a user or technician operating the dishwashing appliance 100.

Referring now specifically to FIG. 5 , a graph of electrical power between the power supply and an exemplary motor type A is illustrated. As may be seen in FIG. 5 , the current draw for motor type A is relatively low, e.g., peaks at about 0.5 Amps (500 mA). Also as may be seen in FIG. 5 , the Back EMF for motor type A is relatively choppy, e.g., includes multiple peaks and valleys, such as one or more spikes, e.g., around 3500 mA (3.5 Amps), before the Back EMF stabilizes, e.g., around 3000 mA (3 Amps) in the example illustrated in FIG. 5 .

Turning now to FIG. 6 , and in contrast with the motor type A of FIG. 5 , a graph of electrical power between the power supply and an exemplary motor type B is illustrated. As may be seen in FIG. 6 , the current draw for motor type A is relatively high, e.g., peaks above 1 Amp (1000 mA), such as at about 1.5 Amps (1500 mA) or more, such as at about 2 Amps (2000 mA). Also as may be seen in FIG. 6 , the Back EMF for motor type B is relatively smooth, e.g., increases steadily until it asymptotically approaches a maximum or steady-state Back EMF, e.g., around 3500 mA (3.5 Amps) in the example illustrated in FIG. 6 .

Thus, it can be seen from the examples illustrated in FIGS. 5 and 6 that a motor type, such as type A or type B, may be detected based on the electrical power between the power supply and the motor while the pump is activated. For example, the motor type may be distinguished based on one or both of the current draw and/or the Back EMF.

Turning now to FIG. 7 , exemplary embodiments of the present disclosure also include methods of operating a dishwashing appliance, such as an exemplary method 400 of operating a dishwashing appliance as illustrated in FIG. 7 . Method 400 can be implemented using any suitable appliance, including for example, dishwashing appliance 100 of FIGS. 1 through 4 . Accordingly, to provide context to method 400, reference numerals utilized to describe the features of dishwashing appliance 100 in FIGS. 1 through 3 will be used below.

As illustrated in FIG. 7 , in some embodiments, a method 400 of operating a dishwashing appliance 100 may include a step 410 of activating the pump for a predefined self-calibration time by supplying electrical power from a power supply to the motor of the pump.

While the pump is activated for the predefined self-calibration time, the method 400 may also include a step 420 of monitoring electrical power between the power supply and the motor. For example, the dishwashing appliance may include a sensor circuit, such as the exemplary sensor circuit 204 illustrated in FIG. 4 and described above. In embodiments where the dishwashing appliance includes a sensor circuit, the electrical power between the power supply and the motor may be monitored with the sensor circuit.

In some exemplary embodiments, the method 400 may further include determining a motor type of the motor based on the monitored electrical power. For example, the motor type may be identified or determined based on one or both of a current draw to the motor and/or a back EMF from the motor, as discussed above with reference to the examples in FIGS. 5 and 6 . In some exemplary embodiments, the step of monitoring electrical power may include monitoring electrical current to the motor. In such embodiments, the method 400 may further include comparing the monitored electrical current to the motor against a threshold. For example, the step of determining the motor type may include determining a first motor type when the monitored electrical current to the motor is greater than the threshold and determining a second motor type when the monitored electrical current to the motor is less than the threshold. As one particular example, the exemplary motor types A and B illustrated in FIGS. 5 and 6 may be distinguished based on a current draw either above the threshold, e.g., Motor B in FIG. 6 , or below the threshold, e.g., Motor A in FIG. 5 , where the threshold may be, for example, about 1 Amp. In some embodiments, comparing the monitored electrical current to the motor against the threshold may include comparing a plurality of instantaneous values of the current to the motor against the threshold during the self-calibration time.

As illustrated in FIG. 7 , method 400 may also include a step 440 of selecting a set of control parameters corresponding to the determined motor type of the motor. For example, control parameters for one or more various motor types may be programmed the controller 160, such as into a memory thereof, and the corresponding control parameters may be loaded or applied when the motor type, e.g., A or B, is identified from the current and/or back EMF. In some embodiments, the set of control parameters may include a conversion table of motor speed settings to electrical switch settings, such as triode settings. For example, the control parameters may include power settings, such as power levels for a switch or triode, such as a triode for alternating current (TRIAC), for the determined motor type. For example, a plurality of tables for translating a motor request percentage (e.g., a percent speed requested) to a power level such as a TRIAC percentage may be programmed into the controller, and the applicable table may be applied based on the determined motor type.

Also as illustrated in FIG. 7 , method 400 may further include a step 450 of activating the pump according to the selected set of control parameters during at least one cycle of the dishwashing appliance. For example, the self-calibration time may be separate and apart from any washing operation or cycle, and the results of the self-calibration process, e.g., the selected control parameters corresponding to the determined motor type, may be applied in one or more subsequent wash cycles or other operations of the dishwashing appliance.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. 

What is claimed is:
 1. A method of operating a dishwashing appliance, the dishwashing appliance comprising a tub defining a wash chamber therein for receipt of articles for washing, a sump positioned at a bottom of the wash chamber for receiving fluid from the wash chamber, a pump in fluid communication with the wash chamber and the sump, the pump comprising a motor, and a sensor circuit, the method comprising: activating the pump for a predefined self-calibration time by supplying electrical power from a power supply to the motor of the pump; monitoring, with the sensor circuit, electrical power between the power supply and the motor while the pump is activated for the predefined self-calibration time; determining, based on the monitored electrical power, a motor type of the motor; selecting a set of control parameters corresponding to the determined motor type of the motor; and activating the pump according to the selected set of control parameters during at least one cycle of the dishwashing appliance.
 2. The method of claim 1, wherein the step of monitoring electrical power comprises monitoring electrical current to the motor, further comprising comparing the monitored electrical current to the motor against a threshold, and wherein the step of determining the motor type comprises determining a first motor type when the monitored electrical current to the motor is greater than the threshold and determining a second motor type when the monitored electrical current to the motor is less than the threshold.
 3. The method of claim 2, wherein comparing the monitored electrical current to the motor against the threshold comprises comparing a plurality of instantaneous values of the current to the motor against the threshold during the self-calibration time.
 4. The method of claim 1, wherein the step of monitoring electrical power comprises monitoring back electromotive force from the motor.
 5. The method of claim 1, wherein the set of control parameters comprises a conversion table of motor speed settings to electrical switch settings.
 6. The method of claim 5, wherein the electrical switch settings are triode settings.
 7. The method of claim 1, wherein the sensor circuit comprises a shunt resistor, an operational amplifier, an amplifier, and a microcontroller.
 8. The method of claim 1, wherein the pump is a circulation pump.
 9. The method of claim 1, wherein the pump is a drain pump.
 10. A dishwashing appliance, comprising: a tub defining a wash chamber therein for receipt of articles for washing; a sump positioned at a bottom of the wash chamber for receiving fluid from the wash chamber; a pump in fluid communication with the wash chamber and the sump, the pump comprising a motor; a sensor circuit; and a controller, the controller configured for: activating the pump for a predefined self-calibration time by supplying electrical power from a power supply to the motor of the pump; monitoring, with the sensor circuit, electrical power between the power supply and the motor while the pump is activated for the predefined self-calibration time; determining, based on the monitored electrical power, a motor type of the motor; selecting a set of control parameters corresponding to the determined motor type of the motor; and activating the pump according to the selected set of control parameters during at least one cycle of the dishwashing appliance.
 11. The dishwashing appliance of claim 10, wherein the step of monitoring electrical power comprises monitoring electrical current to the motor, wherein the controller is further configured for comparing the monitored electrical current to the motor against a threshold, and wherein the step of determining the motor type comprises determining a first motor type when the monitored electrical current to the motor is greater than the threshold and determining a second motor type when the monitored electrical current to the motor is less than the threshold.
 12. The dishwashing appliance of claim 11, wherein comparing the monitored electrical current to the motor against the threshold comprises comparing a plurality of instantaneous values of the current to the motor against the threshold during the self-calibration time.
 13. The dishwashing appliance of claim 10, wherein the step of monitoring electrical power comprises monitoring back electromotive force from the motor.
 14. The dishwashing appliance of claim 10, wherein the set of control parameters comprises a conversion table of motor speed settings to electrical switch settings.
 15. The dishwashing appliance of claim 14, wherein the electrical switch is a triode.
 16. The dishwashing appliance of claim 10, wherein the sensor circuit comprises a shunt resistor, an operational amplifier, an amplifier, and a microcontroller.
 17. The dishwashing appliance of claim 10, wherein the pump is a circulation pump.
 18. The dishwashing appliance of claim 10, wherein the pump is a drain pump. 